The wealth gap comes down to catalog acquisition strategy versus catalog ownership strategy. McCartney didn't just rely on Beatles royalties (which alone are massive); he became a financial player by purchasing publishing rights to 3,000+ songs including Buddy Holly and Everly Brothers classics. This is wealth multiplication through M&A. Wonder, by contrast, made the smarter move at the time—retaining ownership of his master recordings and publishing when most Motown artists were getting fleeced by labels—but he played defense rather than offense. He protected his money; McCartney multiplied it.

Timing and leverage also matter enormously. McCartney had the Beatles brand and already-massive royalty streams to use as collateral and capital for acquisitions starting in the 1970s-80s. Wonder, despite being equally talented and having strong catalog ownership, didn't have the same financial runway to buy other artists' work. His wealth compounded steadily from one source (his own catalog); McCartney's compounded exponentially from multiple sources. It's the difference between owning a printing press versus owning a printing press factory.

The third factor is negotiating power at different eras. McCartney negotiated from a position of unmatched global fame and leverage—he could demand ownership structures that were unthinkable for most artists. Wonder did better than his Motown peers by avoiding exploitative deals, which is why his $200M is genuinely impressive and hard-earned. But McCartney didn't just avoid bad deals; he structured deals that made him a de facto music industry investor. One is a cautionary tale of artist empowerment; the other is a masterclass in financial empire-building.